The present study aimed to assess groundwater quality according to the water quality index (WQI) in Ali Al- Gharbi district of the Maysan Governorate in eastern Iraq. For this purpose, 10 physical parameters such as pH, total hardness ( TH), magnesium (Mg2+), calcium (Ca2+), potassium (K+), sodium (Na+), sulphate (SO42–), chloride (Cl–), nitrate (NO3–), and total dissolved solids ( TDSs) were examined since 2019 from 16 different locations (viz. wells). The analysis results indicated that 18.75% of the water samples were of good quality, 56.25% of them had low quality, and 25% of such samples were very poor. The WQI also varied from 69.67 and 297.6. Therefore, prior to water use, there is a dire need for some treatments, as protecting this district from pollution is significant.

In the study suitability of water quality index approach and environmetric methods in fi ngerprinting heavy metal pollution as well as comparison of spatial variability of multiple contaminants in surface water were assessed in the case of The Gediz River Basin, Turkey. Water quality variables were categorized into two classes using factor and cluster analysis. Furthermore, soil contamination index was adapted to water pollution index and used to fi nd out the relative relationship between the reference standards and the current situation of heavy metal contamination in water. Results revealed that surface water heavy metal content was mainly governed by metal processing, textile and tannery industries in the region. On the other hand, metal processing industry discharges mainly degraded quality of water in Kemalpasa and Menemen. Furthermore, Kemalpasa region has been heavily affected from tannery and textile industries effl uents. Moreover, pollution parameters have not been infl uenced by changes in physical factors (discharge and temperature). This study indicated the effectiveness of water quality index approach and statistical tools in fi ngerprinting of pollution and comparative assessment of water quality. Both methods can assist decision makers to determine priorities in management practices.

Aluminium slag waste is a residue from aluminium recycling activities, classified as hazardous waste so its disposal into the environment without processing can cause environmental problems, including groundwater pollution. There are 90 illegal dumping areas for aluminium slag waste spread in the Sumobito District, Jombang Regency. This study aims to evaluate the quality of shallow groundwater surrounding aluminium slag disposal in the Sumobito District for drinking water. The methods applied an integrated water quality index ( WQI) and heavy metal pollution index ( HPI), multivariate analysis (principal component analysis (PCA) and hierarchical clustering analysis (HCA)), and geospatial analysis for assessing groundwater quality. The field campaign conducted 40 groundwater samples of the dug wells for measuring the groundwater level and 30 of them were analysed for the chemical contents. The results showed that some locations exceeded the quality standards for total dissolved solids ( TDS), electrical conductivity (EC), and Al ²⁺. The WQI shows that 7% of dug well samples are in poor drinking water condition, 73% are in good condition, and 20% are in excellent condition. The level of heavy metal contamination based on HPI is below the standard limit, but 13.3% of the water samples are classified as high contamination. The multivariate analysis shows that anthropogenic factors and natural sources/geogenic factors contributed to shallow groundwater quality in the study area. The geospatial map shows that the distribution of poor groundwater quality is in the northern area, following the direction of groundwater flow, and is a downstream area of aluminium slag waste contaminants.

In this research different methods for measuring water quality indices were conducted to investigate the performance of the newly designed, constructed and operated 9-Nissan water treatment plant, Iraq. Data gathering and implementation took place throughout winter and summer. Water samples were taken periodically, according to the standard method, the re-search was carried out by collecting different random samples for eight months (Jun. 2015–Jan. 2016) and measuring (tur-bidity, total hardness, pH, total dissolved solids, suspended solids, Cl–, Mg2+, Fe2+,NO3–, NH3+) for each sample. Five dif-ferent approaches and methodologies of calculating the water index were applied. The results revealed that the Water Qual-ity Indices varied from 70.55 to 88.24, when applying Canadian Council of Ministers of the Environment Water Quality Index (CCMEWQI) and British Columbia water quality index (BCWQI) geometric weighted mean respectively. All the results, from the five approaches indicated good water quality, multiple regression analyses were conducted for turbidity, total hardness and suspended solids, they found that these parameters are strongly related to each other and to other pa-rameters.

Developments in agriculture, industry, and urban life have caused the deterioration of water resources, such as rivers and reservoirs in terms of their quality and quantity. This includes the Saguling Reservoir located in the Citarum Basin, Indonesia. A review of previous studies reveals that the water quality index ( WQI) is efficient for the identification of pollution sources, as well as for the understanding of temporal and spatial variations in reservoir water quality. The NSFWQI (The National Sanitation Foundation water quality index) is one of WQI calculation methods. The NSFWQI is commonly used as an indi-cator of surface water quality. It is based on nitrate, phosphate, turbidity, temperature, faecal coliform, pH, DO, TDS, and BOD. The average NSFWQI has been 48.42 during a dry year, 43.97 during a normal year, and 45.82 during a wet year. The WQI helped to classify water quality in the Saguling Reservoir as “bad”. This study reveals that the strongest and most significant correlation between the parameter concentration and the WQI is the turbidity concentration, for which the coeffi-cient correlation is 0.821 in a dry year, and faecal coli, for which the coefficient correlation is 0.729 in a dry year. Both parameters can be used to calculate the WQI. The research also included a nitrate concentration distribution analysis around the Saguling Reservoir using the Inverse Distance Weighted method.

The article presents an assessment of the effects of anthropogenic activities on the quality of water in four streams flowing through a camp based on a combined assessment of environmental impacts and the water quality index. The quantitative and qualitative assessment of environmental impact was made after identifying the anthropogenic activities carried out in the camp. The water quality index ( WQI) was calculated after monitoring seventeen physicochemical and microbiological variables and the Montoya index was applied. The samples were collected during 48 sampling campaigns, organised over the period of six months in eight stations. Two stations were located in each stream, one before and one after it passed through the camp. The results indicated that streams 1, 3, and 4 show a slight deterioration in water quality, affected by anthropogenic activities carried out in the said camp; meanwhile, stream 2 shows an increasing deterioration in water quality. The water quality of the streams before passing through the camp was determined to be between “uncontaminated” and “acceptable”, while after passing through the camp it was classified between “acceptable” and “slightly contaminated”. The results indicated a non-significant difference between the downstream and upstream WQI values for streams 1, 3, and 4; while stream 2 did show a significant difference in the WQI between upstream and downstream; indicating that anthropogenic activities alter the quality of the water.